To obtain this achievement you'll first need to be playing as Zer0 and have reached level 5, as being in Decepti0n is his unique Action Skill. Now that you're playing as him, there's one Skill you're going to have to buy from your Skill Tree before you can make it last for 10 seconds or more, so this will take some levelling to reach it.

Below is the Skill you'll have to purchase;

Bloodshed Skill Tree

Many Must Fall: Killing an enemy with a melee attack while Decepti0n is active, causes you to deploy another holographic decoy, re-stealth, and add time to Decepti0ns duration. This can be done multiple times in succession.

Like the Wind: While moving you gain increased melee damage and gun damage.

Required Level: 25

Skill Tier: 5

Skill Upgrade: 5/5

Now that you have that, you're good to go for 10 seconds. All you need now is enough enemies to keep it going. This is easier to get playing solo because then you don't have to worry about other people stealing much need kills.